The present invention relates to an improved debarking arm for use in a log-debarking apparatus.
The usual log-debarking system includes a debarking apparatus having a ring mounted on a support frame for powered rotation about a log-transport axis. Two log-feed assemblies positioned on either side of the apparatus are operable to move a log along this axis through a central opening in the ring in a front-to-rear direction. A plurality of elongate, curved debarking arms are mounted on the ring adjacent their outer ends for swinging of their inner ends toward and away from the transport axis. The arms are normally biased toward inwardly swung positions.
To introduce a log into the apparatus, typically, the log is moved along the transport axis until its front end makes contact with front edge projections extending along front outer end edges of the arms. The combined rotative movement of the arms and the forward movement of the log acts to open the arms--that is, spread the inner arm ends away from the transport axis--to allow log entry into the central opening in the ring. At this point, the surface of the log is embraced by the arms, with debarking tips in the arms being biased against the log surface. Debarking occurs by the action of these tips circulating about the log surface as the log is moved axially in a front-to-rear direction.
It can be appreciated that the debarking arms in such an apparatus may be subjected to extreme forces in the direction of log movement, both by the initial arm-opening event and during the actual debarking operation. The accumulated effect of such forces produces arm fatigue which can damage an arm. Prior art debarking arms generally have a solid, curved bar construction which is quite durable, and which effectively prevents an arm from being damaged by repeated longitudinally directed forces. The solid arm construction, however, adds significantly to the weight of a log-debarking apparatus. Excessive weight is a particularly troublesome problem in that it produces significant centrifugal forces on arms with the debarking ring rotating. Such forces are counterproductive in that they must be overcome in order to create the necessary debarking forces at the arms' debarking tips.
One general object of the present invention is to provide, for use in a log-debarking apparatus of the type described above, a hollow substantially closed, debarking arm which is both lightweight and strong.
A related object of the invention is to provide such an arm having an angled wall portion which serves both to reduce the weight of the arm, and to increase its strength against forces encountered in a log-debarking operation.
Still another object of the invention is to provide such an arm which is interchangeable, in a log-debarking apparatus, with a solid debarking arm of the type known in the prior art.
The debarking arm of the present invention is intended for use in a log-debarking apparatus having a ring which is rotatable about a transport axis as a log is moved along this axis through an opening in the ring in a front-to-rear direction. The arm includes an elongate, curved hollow section extending between an inner end adapted to carry a debarking tip, and an outer end adapted to be mounted on the ring for swinging of the arm's inner end toward and away from the transport axis. The structure has a front edge portion, which, with the arm in an operative position on the ring, inclines rearwardly progressing toward the inner arm end, and a front wall portion which slopes rearwardly progressing from this edge portion in a direction away from the transport axis. A curved log-engaging edge projection extends along and projects forwardly from the arm's edge portion, to engage a log during initial log contact.
These and other objects and features of the present invention will become more fully apparent when the following detailed description of a preferred embodiment of the invention is read in conjunction with the accompanying drawings.